Apparatus for false twisting yarn



Oct. 10,1967

R. s. GILCHRIST I 3,345,811

APPARATUS FOR FALSE TWISTING YARN Filed Dec. 1, 1964 4 Sheets-Sheet 1 Oct. 10,1967 R. s. GILCHRIST 3,345,811 1 APPARATUS FOR FALSE TWISTING YARN 4 Sheets-Sheet 2 Filed Dec. 1, 1964 Oct-10,1967 R. $.GILCHRIST 3,345,811

APPARATUS FOR FALSE TWISTING YARN Filed Dec. 1. 1964 4 Sheets-Sheet s 46 I 45 44- l I I; 2342 42 I 4 7 4 4'6 43 Oct. 10,1967 R. s. GILCHRIST 3,345,811

APPARATUS FOR FALSE TWISTING YARN Filed Dec. 1. 1964 4 Sheets-Sheet 4 United States Patent 3,345,811 APPARATUS FOR FALSE TWISTING YARN Reginald Selby Gilchrist, London, England, assignor to The Klinger Manufacturing Company, Limited, London, England, a British company Filed Dec. 1, 1964, Ser. No. 414,957 Claims priority, application Great Britain, Nov. 29, 1963, 47,321/63 11 Claims. (Cl. 57--77.45)

This invention relates to improvements in or relating to the false twist crimping of thermoplastic yarn or yarn having a thermoplastic component.

An object of the present invention is to provide apparatus for false twist crimping yarn whereby a high degree of crimp is imparted to the yarn.

It is another object of the present invention to provide apparatus for false twist crimping yarn wherein irregularities or imperfections in the flat yarn, i.e. the yarn before it is false twist crimped, as a result of previous manufacturing or processing thereof, are minimised in their effect upon the finished qualities of the yarn such as the knitting or dyeing characteristics of the yarn.

A further object of the present invention is to provide apparatus for false twist crimping weak yarns having a low tenacity such as di-acetate or tri-acetate yarns, which yarns are not capable of having a high degree of crimp imparted thereto because of their inability to withstand, at the necessary setting temperatures, the tension required to ensure grip between the yarn and the false twisting device at the degree of twist required in order to crimp the yarn.

Yet a further object of the present invention is to provide apparatus for false twist crimping yarn wherein the yarn is allowed to shrink within the heating zone to the extent determined by the temperature of the yarn within that zone.

Yet another object of the present invention is to provide apparatus capable of imparting twist at speeds of up to 800,000 twists per minute and more in travelling yarn.

It is also an object of the present invention to provide a false twisting head, by which expression is meant that part of the apparatus used for continuously false twisting yarn which imparts the twist to the yarn. A plurality of false twisting heads are commonly spaced apart along a false twist apparatus, each being adapted to impart twist to one or more yarns travelling through the apparatus. In accordance with previous proposals each of the heads of the present invention may be adapted to be driven from a common power source by means of a transmission such as a belt drive, or alternatively a power source may be provided for each false twist head.

Still another object of the present invention is to provide a false twisting head through which yarn may pass without the yarn being twisted.

Still a further object of the present invention is to provide a false twisting head which requires no-pre-tension to be imparted to the yarn passing therethrough in order that the head can grip and thereby rotate the yarn and in which the operating surfaces which contact the yarn position and control the yarn.

According to one aspect of the present invention the yarn is passed over or through a heating or setting zone whilst under a low tension so as'to allow the yarn to shrink to an excess dependent upon the temperature to which the yarn is heated and subsequently the yarn is passed through a false twist device, the yarn entering the false twist device at substantially the same low tension at which it passed over or through said heating or setting zone.

The yarn can be rotated by frictional contact with a plurality of endless friction tracks arranged to engage and 3,345,811 Patented Oct. 10, 1967 rotate the yarn without pre-tension being applied thereto, said tracks moving at such a rate that slip occurs between the tracks and the yarn, the frictional engagement of the tracks upon the yarn being such that a predetermined maximum number of twists per unit length are inserted to the yarn. The yarn can be rotated by the false twist device at such a rate and under such conditions that any increase in the amount of twist in the yarn would require an increase in torque to be applied to the yarn that is greater than the false twist device is capable of imparting to the yarn so that there is no increase in the amount of twist imparted to the yarn when the rate of passing the yarn through the false twist device is decreased. The crimped yarn can be formed into a conical package, the rate of passing the yarn through the false twist device being variable between these speeds required to form the conical package without affecting the amount twist imparted to the yarn.

The yarn can be contacted at a plurality of locations spaced apart in the axial direction of the yarn by tracks moving transverse to the axial direction of the yarn, adjacent tracks contacting the yarn on opposite sides thereof so as to impart rotation to the yarn. Adjacent tracks can be moving in opposite directions, and the tracks can move at a peripheral speed of between one and one half and three and one half times the rate of travel of the yarn through the false twist device. Preferably the tracks move at a peripheral speed of between two and three times the rate of travel of the yarn through the false twist device.

The yarn may be withdrawn from a supply package of flat yarn and passed over guide means and/or twist stop means, which prevents the twist in the yarn from running back to the supply package, without substantially increasing the tension in the yarn prior to passing to the heating zone, or the yarn may be withdrawn from a supply package of fiat yarn by feed means, said feed means positively feeding the yarn to the heating zone at a predetermined rate. The tension in the yarn can be not more than .09 gm. per denier and is preferably between .01 gm. per denier and 0.7 gm. per denier.

The movable tracks can co-operate to locate the yarn as it passes through the false twist device and so provide a stable yarn path irrespective of variations in frictional contact between the yarn and the movable tracks. The yarn can pass in a zig-zag manner through the false twist device, the yarn being deflected at each location at which it is contacted by said movable tracks. The deflection of the yarn at each location can be adjustable to vary the frictional grip between the yarn and the movable tracks. The deflection of the yarn at said locations can be less at each location as it passes through the false twist device so that as the yarn tension increases the angle of contact and pressure of the yarn upon the tracks is reduced. The tension in the yarn can increase as it passes through the false twist device.

Alternate annular rings can be rotatable about common axes and the paths of movement of adjacent tracks at their points of contact with the yarn can be in opposite directions.

According to another aspect of the present invention the apparatus for false twist crimping yarn comprises means for passing the yarn from a supply package of yarn to a heating or setting zone, the tension in the yarn in said zone being that required to draw the yarn from said supply package and means for imparting twist to the yarn by passing it in contact with a plurality of endless tracks formed by the bores of a plurality of annular rings ro tatable about axes trans-verse to the direction of travel of the yarn as it passes in contact therewith, the yarn contacting overlapping portions of said tracks so that the yarn is constrained to travel in a tortuous path between alternate tracks, the yarn being contacted on opposed sides by adjacent tracks, the amount of overlap of said tracks being such that a high degree of twist is imparted to the yarn within the heating zone when the peripheral speed of said tracks is between two and three times the rate of travel of the yarn.

According to a further aspect of the present invention means adapted to impart twist to a travelling yarn comprises a plurality of endless friction tracks spaced apart in the direction of travel of the yarn therethrough, adjacent tracks being spaced apart in a direction transverse to the direction of travel of yarn so that in operation the yarn follows a tortuous path between adjacent tracks and is contacted and engaged by portions of said tracks, alternate tracks being substantially in line when viewed in the direction of travel of the yarn. Adjacent tracks can be adapted to travel in opposite directions at the points of contact of said tracks with the yarn.

Each endless friction track is formed by the inner bore of an annular ring; the annular rings can be rotatable about parallel axes and alternate annular rings can be rotatable about a common axis.

Adjacent tracks may be spaced apart transverse to their axes of rotation so as to overlap, the overlapping portions of the tracks co-operating to define a space therebetween having a maximum width not greater than the diameter of yarn to be twisted; or adjacent tracks can be spaced apart transverse to their axes of rotation so that adjacent portions of adjacent tracks are offset and do not co-operate to define an enclosed space therebetween when viewed in the direction of the axes of rotation of the tracks.

The distance between the two common axes of rotation of the tracks can be adjustable to vary the distance by which said tracks are spaced apart in the direction transverse to their axes of rotation. The tracks can be movable in the direction transverse to the direction of travel of the yarn between the operating position and a position such that the yarn would travel through the means without contacting said tracks; there can be three or more tracks.

According to yet another aspect of the present invention there is provided a false twist head comprising four or more tracks formed by the inner bores of annular rings spaced apart in the direction of travel of yarn therethrough. Adjacent tracks can be of equal diameter and the distance between said common axes can be adjustable.

The distance between said common axes can be adjustable from an operating position to an inoperative position such that said distance is less than the sum of the radii of two adjacent tracks minus the diameter of the yarn to be twisted; stop means can be provided to limit the distance between said common axes to a predetermined operating position.

The annular rings can be supported at their outer peripheries by grooved rollers one or more of which rollers can be driven rollers and the remainder idler rollers. A plurality of grooved rollers can be rotatable about common axes so as to support a plurality of annuli rotatable about common axes. An endless belt or band can engage a groove in at least one of the driven rollers; said endless belt or band engaging a groove in the idler rollers.

The annular rings can be formed from metal: the inner bores of the annular rings can be formed from a nonmetallic wear resisting friction material. The tracks can be convexly curved in cross-section and may be curved so that a tangent from the curved track of one annular ring to the curved track of the adjacent annular ring contacts each of said tracks at adjacent edges thereof.

The annular rings can be spaced apart in the direction of travel of the yarn therethrough by a distance less than the width of said rings in that direction.

The diameter of the tracks can vary from one end of the assembly to the other to vary the distance by which adjacent portions of adjacent tracks are spaced apart. In this way adjacent tracks can be spaced apart less at the input end of the assembly than at the output side thereof.

According to yet a further aspect of the present invention there is provided a false twist head for twisting a plurality of yarns comprising a first set of tracks formed by the inner bores of a set of annular rings spaced apart and supported to rotate about a first axis, a plurality of further sets of tracks similar to said first set and supported to rotate about axes parallel to said first axis and spaced therefrom so that the annuli of each set overlap the annuli of at least one other set, adjacent portions of the tracks of overlapping annuli together forming tortuous paths through which yarns pass in operation and are contacted and rotated by said tracks.

According to still another aspect of the present invention there is provided an apparatus for false twisting yarn comprising a number of endless friction tracks each having an inner face movable around and exposed to a space within it which tracks are arranged opposite one another, out of register and spaced apart so that considering two neighboring tracks and viewing through the spaces, the inner face of a portion of one on one side of its space is disposed adjacent an inner face of a portion of the other track which lies on the opposite side of its space to that (side of the latter where the first said portion lies so as to provide two faces across which the yarn may extend and is firmly engaged on opposite sides thereof by said faces.

In a preferred arrangement said friction tracks and the spaces encompassed by said tracks comprise faces of bores formed in a number of rotatable members mounted to rotate about substantially parallel axes which members are so axially and radially displaced from one another that considering two adjacent members and viewing them along said axes, a portion of the bore of one member lying on one side of its axis of rotation is disposed adjacent a portion of a bore of the other rotatable memberwhich latter portion of the bore lies on the opposite side of the axis of rotation of its member to that of the first member, so that when the yarn is threaded through those two portions of the bore and extends in a general direction of the axes of rotation it is contacted on opposite sides thereof by said portions of the bores, and means for rotating said members in such manner as to impart rotation to the yarn.

The friction tracks are arranged to rotate in the same direction with respect to a fixed part of the apparatus.

In one such arrangement said rotatable members are so mounted that said portions of the bores of adjacent rotatable members overlap to provide a space through which the yarn passes and which space as viewed in the direction of said axes has a maximum width less than the diameter of the yarn whereby the path of travel of the yarn from one bore to another is substantially straight.

Alternatively said rotatable members are so mounted that said portions of the bores of adjacent rotatable members are ofi-set from one another so that as viewed along the axes of rotation of said members there is no apparent space between said portions so that the path of travel of the yarn is deflected from a straight line as it passes from one bore to another.

The aforesaid mounting for the rotatable members may be provided with means for adjusting the width of the aforesaid spaces or the amount of off-setting between said portions of the bores.

The aforesaid rotatable members in axial cross-section may be provided with convexly curved inner surfaces which engage the yarn.

The rotatable members may be in the form of annuli.

The means for rotating said members may be such that portions of the two bores which engage opposite sides of the yarn are moving in opposite directions with respect to a fixed part of the apparatus.

The means for imparting rotation to the rotatable members comprises a number of spindles extending substantially parallel to the axes of said bores and having parts thereon in frictional engagement with the outer peripheries of said members and/ or with the bores thereof and means for driving at least one of the spindles.

In such an arrangement a number of pairs of annuli may be provided so that one of the annuli in each pair is co-axially arranged with respect to an annulus in each of the other parts, and the two annuli in each pair are so mounted that portions of their peripheries on opposite sides thereof overlap one another and which mountings for the annuli may comprise grooved rollers or tracks on spindles into which grooves, the peripheries 'of the annuli extend so the peripheries of the annuli are frictionally engaged by the bottoms of the grooves. The spindles may be rotated by an endless driving band which engages driving pulleys fixed to the spindles certain of which pulleys may also constitute the grooved rollers for engaging the peripheries of the annuli and means are provided for driving one of said spindles through a suitable transmission from a motor.

The spindles may be adjustably mounted on a base member so as to be movable towards and away from said annuli and the belt may be of a resilient character.

The aforesaid annuli may be formed from hard rubber or rubber like plastics and said grooved rollers or the like may be of metal.

Alternatively the annuli may be formed from metal and be provided on at least the inner peripheries thereof with non metallic wear resisting friction material for example a polyurethane rubber.

The present invention will now be described with reference to the accompanying diagrammatic drawings in which:

FIGURE 1 is a diagrammatic layout of a false twisting apparatus for false twist crimping yarn;

FIGURE 2 is a diagrammatic layout of an alternative arrangement of part of the apparatus shown in FIG- URE 1;

.FIGURE 3 is a plan view of one form of apparatus for twisting a travelling yarn;

FIGURE 4 is a sectional elevation along the line IVIV of the apparatus shown in FIGURE 3;

FIGURE 5 is a plan view of another form of apparatus for twisting a travelling yarn;

FIGURE 6 is a sectional elevation along the line VIVI of the apparatus shown in FIGURE 5;

- FIGURE 7 is a plan view of an alternative arrangement similar to that shown in FIGURE 5;

.FIGURE 8 is a. sectional elevation along the line' VIIIVIII of the apparatus shown in FIGURE 7 and FIGURE 9 is a plan view of an arrangement for twisting travelling yarn at two positions.

Referring to FIGURE 1 yarn 10 from a supply package of yarn 11 passes through guide means 12 and around twist stop means 13 which prevents twist in the yarn from running back to the supply package and which is also capable of imparting a very small amount of tension to the yarn. Alternatively additional means may be included which imparts a small amount of tension to the yarn. The yarn then passes through a heating or setting zone 14 wherein the temperature of the yarn is raised and then to a false twisting means 15 which as shown may conveniently be driven by a belt transmission 16 bearing against a shaft 17 extending from the head 15 and driving the twisting means within the head. The yarn then passes through the nip of a pair of feed rollers 18 which draw the yarn from the supply package and through the aforesaid components of the apparatus. From the feed v The tension in the yarn in the heating zone up to its,

entry into the false twist device is only that which is required in order to control the path of travel of the yarn through the zone, and not more than 0.09 gm. per denier of the yarn. Such a tension is generally imparted to the yarn by reason only of it being drawn from the supply package and passed over or through the guide means and the twist stop device. It may, however, be found to be desirable with heavy denier yarns, for example above 300 denier, to impart a very small additional tension to the yarn in order to obtain the degree of control required to control the path of travel of such yarns. Such a tension would still be less than .09 gm. per denier.

At this low tension the yarn can shrink within the heating zone to the extent dependent upon the temperature of the yarn, its own characteristics and the tensional strains imposed upon it by the twisting action of the false twist device. In this way the set of the yarn is improved and a more even crimp obtained. The characteristics of a fiat or untwisted yarn may vary throughout or along its length. When the yarn is subjected to a predetermined tension in the heating zone these variations can affect the potential shrinkage of the yarn and therefore the crimp which is imparted to the yarn. Under certain circumstances these variations in the flat yarn characteristics may be accentuated by the false twist crimping process with the result that the finished yarn exhibits varying characteristics such as dye up take and crimp rigidity which have a deleterious effect upon the finished article into which the yarn is formed.

By passing the yarn through the heating zone under conditions of substantially no tension the effect of variations in the flat yarn characteristics .on the finished product are minimised or eliminated.

The apparatus of the present invention also enables weaker yarns to be processed. Hitherto attempts to false twist crimp yarns such as di-acetate or tri-acetate yarns by known false twist processes have not proved entirely satisfactory because of the tendency of the yarns to break when subjected to the combination of conditions of tension, heat and twist whilst in the setting zone. In attempting to overcome this a filament of a stronger yarn such as nylon has been included with the weaker filaments but, in general, attempts to overcome the problem have resulted in yarns of low crimp rigidity. By heating the yarn whilst under low tension the optimum amount of twist may be imparted to such yarns.

In the arrangement shown in FIGURE 2 a pair of feed rollers 21 are shown by which means the yarn 10 can be unwound from the supply package 11 and positively fed into the heating zone 14. The feed rollers are effective as a twist stop to prevent twist in the yarn from running back to the supply package and can be set according to the shrink characteristics of the yarn to feed the yarn to the heating zone at a predetermined rate such as to control the tension in the yarn to the minimum tension necessary to control the path of travel of the yarn.

FIGURES 3 and 4 show one form of false twist head according to the present inventionin which there are provided a number of pairs of annuli 22, 23; 22a, 23a; etc.

The annuli in each pair are displaced both radially and axially so that the inner peripheries 24, 24a etc., of the annuli 22, 22a etc. on the right hand side of the space within the annuli are disposed adjacent to the inner 'peripheries 25, 25a etc. on the left hand side of the space within the annuli 23, 23a etc. The inner peripheral edge of each annulus may be convexly curved in cross-section so that the yarn may pass substantially tangentially from the curve of one annulus to the curve of the adjacent annulus across the gap between them.

The various pairs of annuli 22, 23; 22a, 23a etc. are:

supported by grooved rollers 26, 27, 28 and 29 secured to shafts 30, 31, 32 and 33 which are in turn rotatably mounted on a base plate 34 so that each annulus is supported around its outer periphery by three rollers. Thus the up-,

permost annulus 22 is supported by the three rollers 26, 28 and 29 and the uppermost annulus 23 is supported at a lower level by the three rollers 27, 28, 29. As can be seen from FIGURE 3 each of the grooved rollers 26, 27, 28 and 29 have a number of grooves therein and the rollers 28 and 29 support all the annuli. The pairs of annuli 22a, 23a etc. are similarly supported by grooves in the rollers 26, 27, 28 and 29. Certain grooves in the rollers 26 and 27 do not support any of the annuli and can be omitted. Around each of the rollers passes an endless belt 36. The shaft 31 is extended below the base place 34 and is provided with a sleeve 35 formed of a hard wearing friction material which, in operation, contacts a fiight of the driving belt 16. The shaft 31 is fixed relative to the base plate and means 37 are provided for adjusting the position of shaft 30 towards and away from the shaft 31 in order to vary the overlap of the annuli. Shafts 32 and 33 are urged by means 38 and 39 towards each other so that the grooved rollers maintain contact with annuli when the shaft 30 is adjusted as aforesaid.

The base plate may be bolted or pivotted to the frame of a false twist apparatus by means of a hole 40 in the base plate.

In operation the shaft 31 is rotated by the sleeve 35 contacting the moving belt 16, the endless belt 36 rotating idler rollers 27, 28 and 29.

With this form of construction of false twist head yarn may be fed thereto without the need of pre-tensioning the yarn in order that the rotating tracks grip the yarn. Also the peripheral speed of the yarn relative to the rate of travel of yarn through the head and the amount of overlap of the tracks may be adjusted so that optimum twist is imparted to and set in the yarn. For example the peripheral speed of the tracks may be between one and one-half and three and one-half times the speed of the yarn, preferably between 2 and 3 times the speed of the yarn. By operating within this range, and adjusting the amount of overlap of the tracks to vary the grip of the tracks on the yarn, the yarn can be highly twisted.

Furthermore it will be appreciated that under these conditions slip can take place between the tracks and the yarn. Because of this slippage the rate of travel of the yarn through the head may vary within reasonable limits without substantially affecting the crimp produced in the yarn.

This aspect of the present invention is particularly advantageous when the throughput of yarn is required to be varied to enable the processed yarn to be formed into a conical package. The maximum throughput speed of yarn when winding a cone at a constant peripheral speed is that required at the larger diameter of the cone. In the present invention the yarn may be processed at the speed determined by the winding operation without substantially varying the crimp produced in the yarn and a conical package formed directly on the false twisting machine, the slippage taking place between the yarn and the tracks increasing as the through-put speed decreases.

Preferably the yarn contacts the inner edge of each of the annuli across its complete width so that the distance between adjacent points of contact or adjacent annuli is not substantially greater than the gap between said adjacent annuli. In this way the yarn path is more closely controlled by the surfaces of the tracks. It should also be noted that the yarn is constrained to travel in its path by the operating surfaces of the tracks, which condition is more readily seen in FIGURE where the overlap of the annuli is indicative of that required to twist a heavy denier yarn. The maximum width of the space between two tracks engaging the yarn between them is not normally greater than the diameter of yarn to be twisted.

It is also preferable that the tracks are spaced apart vertically by only that distance necessary for the yarn to pass from one track to the next in order to more closely grip the yarn passing therethrough.

FIGURES 5 and 6 show another arrangement for supporting and rotating a set of annuli disposed relative to each other as in FIGURES 3 and 4. As shown a base plate 41 is provided with a hole 40 by which it can be bolted or mounted upon the frame of a false twist machine. Rotatably mounted on the base plate are two shafts 42 and 43 on which are secured rollers 44 and 45 having flanges 45 and 47 respectively at each end. Between the rollers 44 and 45 is an endless belt or band 48 formed from rubber or a rubber-like flexible friction material having a fiat outer surface 49 which contacts the rollers 44 and 45 and formed on its inner surface with a series of parallel grooves 50, 50a etc. in which annuli 22, 23, 22a, 23a etc. are supported. Alternate annuli are supported to rotate about a common axis. The shaft 42 is fixed relative to the base plate and adjusting means 51 are provided to adjust the shaft 43 along the line joining their axes to vary the amount of overlap of the annuli; the belt 48 extending in length to allow the axis of rotation of the annuli to become farther apart, and vice versa.

Shaft 42 is extended through the plate 41 has as before a sleeve 35 secured thereto which, in operation, contacts a flight of a moving belt 16 and rotates the shaft, the belt 48* and hence the annuli 22, 23; 22a, 23a etc. A hole 52 is provided in the base plate through which yarn may pass.

FIGURES 7 and 8 shown an alternative arrangement similar to that shown in FIGURES 5 and 6 wherein the annuli are supported within an endless belt 48. In this arrangement, however, the annuli are further supported at their outer peripheries by rollers 53 and 54 which are secured to shafts 55 and 56' rotatably supported on the base plate 41. The rollers 53 and 54 may be of plain diameter or they may be grooved rollers as are shown for example in FIGURE 4. An extensible belt 57 passing around a pulley 58 on the driven shaft 42 passes around pulleys 59 and 60 on the shaft 55 and 56 and a pulley 61 on the shaft 43. By this construction the annuli are more stable when rotated at high speeds.

A false twist head constructed as shown in FIGURES 3 and 4 was made with the annuli of 1 /2 inches outside diameter and an inner diameter of 1 inch. The driving roller was inch dia. At a throughput of yarn of 20 0 feet per minute a ring speed of 1900 rpm. was employed using a driving roller speed of 3800 rpm. Yarn of denier was passed through the head the tension in the yarn prior to entering the head being less than 1 gm. The amount of overlap was adjusted until a high degree of twist was imparted to the yarn by the false twist head. Crimped yarn produced in this manner was found to exhibit a high degree of crimp rigidity and a high strength.

In this construction the annuli were formed of metal and Were provided on their inner peripheries with a non metallic wear resisting friction surface of polyurethane rubber in the form of inserts pressed into the annular rings. By maintaining the inserts under compression the abrasion resistance is increased. Preferably the inserts have a polished surface which contacts the yarns.

In the case where it is required to false twist a number of yarns in a single assemblage further sets of annuli can be grouped around the first pair, one set of annuli rotating about a first axis overlapping and overlapping co-operating with a further two sets of annuli.

Such an arrangement is shown in FIGURE 9 which is basically similar to the arrangement shown in FIG- URES 3 and 4. As shown a further set of annuli 62, 62a, etc. of which only 62 can be seen, are supported by a further grooved roller secured to a shaft 64 rotatab-ly mounted on the base plate 34 and by the two grooved rollers 27 and 29 which also serve to support the annular rings 23, 23a etc. of which only 23 can be seen. As before rollers 28 and 29 are urged together by means 9 38 and 39 and roller 27 can be adjusted to vary the overlap of the annuli 22 and 23. In addition roller 27 is adjustable by means 65 to vary the overlap of the annuli 62 and 27, the roller 63 being urged towards the annuli 62 by means 66. The endless belt 36 extends around the roller 63.

In order to assist in threading up the apparatus means 67 as shown in FIGURE may be included to rapidly bring the supporting roller 47 towards the roller 46 thereby increasing the overlap of the annuli to an inoperative position such that a large enough space 68 exists between the annuli to facilitate the passage therethrough of a rigid threading hook or the like. Stop means may be included so that operation of the means 6-7 does not upset the adjustment of the means 51 when the annuli are returned to the operating position on releasing the means 67.

What I claim is:

1. Apparatus for imparting a twist to a length of travelling yarn, said apparatus comprising a first endless track having an inner yarn engaging surface moving in a first plane substantially at right angles to the general direction of yarn travel, a second endless track having an inner yarn engaging surface moving in a second plane displaced from and substantially parallel to said first plane, drive means arranged to support and move said first and second endless tracks, said first and second endless tracksbeing so disposed that the yarn is diverted by said first and second inner yarn engaging surfaces of said first and second tracks in opposite directions and twist is imparted to the yarn .by contact with said first and second inner yarn engaging surfaces.

2. Apparatus according to claim 1, wherein said endless tracks comprise annular members.

3. Apparatus for imparting a twist to a length of travelling yarn, said apparatus comprising a plurality of first endless tracks having inner yarn engaging surfaces moving in respective first planes substantially at right angles to the general direction of yarn travel, a plurality of second endless tracks having inner yarn engaging surfaces moving in respective second planes between and substantially parallel to said first planes, drive means arranged to support and move said plurality of first endless tracks and said plurality of second endless tracks, said plurality of endless tracks being so disposed that the yarn is diverted by said first and second inner yarn engaging surfaces of said first and second plurality of tracks in opposite directions and twist is imparted to the yarn by contact with said first and second plurality of inner yarn engaging surfaces.

4. Apparatus according to claim 3, wherein said first and second plurality of endless tracks comprise annular members.

5'. Apparatus according to claim 4, including support means comprising pulley means and wherein said drive means comprises a grooved flexible member engaged by said pulley means, said annular members being supported in the groove of said flexible member.

6. Apparatus according to claim 4. including support means comprising grooved pulley means, and wherein said drive means comprises a flexible member engaged by said pulley means, said annular members being supported in grooves of said pulley means.

7. The apparatus in accordance with claim 4 wherein said drive means comprises pulley members frictionally engaging and supporting said annular means for movement thereof and an endless belt, the inner surface of which frictionally engages and supports only said pulley means.

8. The apparatus in accordance with claim 7 wherein each said annular member is supported and driven by a set of three pulleys spaced about the periphery thereof each said pulley set having two members common to said adjacent pulley set whereby said common members support and move two adjacent ones of said annular members.

9. The apparatus in accordance with claim 4 wherein said drive means comprises an endless belt, the inner surface of which friction-ally engages and supports said annular members and pulley means frictionally engaging and supporting the outer surface of said belt.

10. The apparatus in accordance with claim 4 wherein said drive means comprises a first endless belt, the inner surface of which frictionally engages and supports said annular members, pulley means frictionally engaging and supporting the outer surface of said first belt and a second endless belt frictionally engaging and supporting only said pulley means.

11. The apparatus in accordance with claim 1 including means to adjust the axis of at least one of said drive means with respect to the other said drive means.

References Cited UNITED STATES PATENTS 1,030,179 6/ 1912 Hilden 5777.4 2,557,104 6/1951 Hegedus 5777.33 2,923,121 6/1958 Tully 5777.4 2,936,570 5/1960 Arthur et al. 5777.4 2,939,269 6/1960 Dobson 5777.4 3,021,663 2/1962 Findlow 5777.4 3,066,473 12/1962 Maeda 5777.4 3,103,097 9/1963 Meili et al. 5777.4 3,114,231 12/1963 Selling et al. 5777.4 X 3,137,119 6/1964 C-rouzet 57157 3,180,074 4/1965 Smith 5777.33 X 3,196,602 7/1965 Jenkins 57-157 3,228,181 1/1966 Paterson 5777.4 X

FOREIGN PATENTS 1,183,720 2/1959 France. 1,268,325 6/1961 France. 1,285,433 1/1962 France.

988,093 4/ 1965 Great Britain.

998,770 6/1965 Great Britain.

STANLEY N. GILREATH, Primary Examiner. FRANK J. COHEN, Examiner. A. J. SIDOTI, D. WATKINS, Assistant Examiners, 

1. APPARATUS FOR IMPARTING A TWIST TO A LENGTH OF TRAVELLING YARN, SAID APPARATUS COMPRISING A FIRST ENDLESS TRACK HAVING AN INNER YARN ENGAGING SURFACE MOVING IN A FIRST PLANE SUBSTANTIALLY AT RIGHT ANGLES TO THE GENERAL DIRECTION OF YARN TRAVEL, A SECOND ENDLESS TRACK HAVING AN INNER YARN ENGAGING SURFACE MOVING IN A SECOND PLANE DISPLACED FROM AND SUBSTANTIALLY PARALLEL TO SAID FIRST PLANE, DRIVE MEANS ARRANGED TO SUPPORT AND MOVE SAID FIRST AND SECOND ENDLESS TRACKS, SAID FIRST AND SECOND ENDLESS TRACKS BEING SO DISPOSED THAT THE YARN IS DIVERTED BY SAID FIRST AND SECOND INNER YARN ENGAGING SURFACES OF SAID FIRST AND SECOND TRACKS IN OPPOSITE DIRECTIONS AND 